Contact sports, such as football, require the use of helmets to protect players from head injuries caused by impact forces sustained during games or practice. In recent years, a degenerative disease known as chronic traumatic encephalopathy (CTE) has been diagnosed in many retired players of contact sports. While the scientific analysis and characterization of CTE is ongoing, cumulative concussions are believed to cause the physical manifestations of CTE including atrophy of certain regions of the brain. Even numerous sub-concussive events are thought to contribute to CTE. For example, collisions between defensive and offensive linemen in football rarely render players completely unconscious, but numerous sub-concussive impacts may accumulate and contribute to CTE. Spurred by new knowledge of CTE and CTE's effect on players, the importance and effectiveness of helmet technology has become paramount to the health of sports players and others.
Several types of helmets have been used in the sport of football ever since players began wearing helmets. Early football helmets were made from hardened leather. Modern helmets are made from plastic and generally include a shock absorbing liner within a plastic shell, a face guard, and a chin strap that fits snugly on the chin of a player to secure the helmet to the player's head.
An example of a prior art device may be found in U.S. Patent Publication No. 2014/0000011, which discloses a helmet having cells filled with an attenuating fluid such as CO2, air, or water. An accelerometer on each cell may detect an impact and a microcontroller opens an exhaust valve on the cell, which allows the cell to discharge the attenuating fluid in an effort to absorb some of the impact. The cells must be pre-filled with the attenuating fluid. Therefore, a player must return to the sideline after each impact that triggers a release of attenuating fluid. This interruption can negatively affect the play of the game when players are routinely exiting and entering the field of play.
Another example of a prior art device may be found in U.S. Patent Publication No. 2012/0304367, which discloses a helmet with a protective bladder and relief valves. If the pressure in the bladder is greater than a threshold pressure, then the relief valve is opened to evacuate the contents of the bladder to help absorb an impact. However, there is no system or protocol for a post-impact inflation of the bladder. During a football game, a player may experience a first impact early in a play and then a second impact later in the play. If the bladder remains deflated for the second impact, then the player is at an increased risk of experiencing a concussive or sub-concussive impact that can contribute to CTE.
While the prior art may be adequate for its intended purposes, there is still a need for a protective helmet that provides better protection to reduce impact forces sustained by helmet wearers. There is also a need for a protective helmet that provides optimal brain protection for a wearer in which the protective helmet can be re-set or otherwise returned to a ready state by fluid bladders or reservoirs that deflate upon impact but are then automatically re-inflated after an initial impact.